hi , before i buy GravityForm i have question about input mask and how could we limit characters or allow only special characters and numbers for field
In addition to using the input mask feature you mention here, you can also use the filter gform_validation or gform_field_validation to run the values through any PHP function prior to submission and use the filter gform_validation_message to return specific messages related to any failure.
HI @arioman. You can set up a free demo to try Gravity Forms and any other custom code you want (you can edit the theme functions.php file on the demo site.) You can use the following link to spin up a demo site where you can test Gravity Forms and all the official add-ons for several days: https://www.gravityforms.com/demo/
You’re also welcome to purchase a license and try it out on your own site and if turns out that Gravity Forms does not work for your use-case, you can always request a refund within the first 30 days of purchase.